Syncronous switching regulator control circuit

Abstract

A switching regulator includes a first switching regulator corresponding to a master channel, and a second switching regulator corresponding to a slave channel. The first switching regulator generates first output voltage Vout 1 by a constant on-time system in which on-time is constant. On the other hand, the second switching regulator monitors a first switching signal and a second on-time control circuit determines on-time of a second switching signal in accordance with lapse time from the rising time of the first switching signal to the rising time of a second switching signal.

1. A switching regulator control circuit comprising:
 a first output circuit arranged to output a first output voltage in response to a first switching pulse signal; 
 a first switching signal generating circuit arranged to output the first switching pulse signal in response to the first output voltage; 
 a second output circuit arranged to output a second output voltage in response to a second switching pulse signal; and 
 a second switching signal generating circuit arranged to output the second switching pulse signal in response to the second output voltage and the first output voltage and arranged to change on-time of the second switching pulse signal in response to the first switching signal. 
 
     
     
       2. The switching regulator control circuit according to  claim 1 ,
 the first switching signal generating circuit comprising: 
 a first voltage comparator arranged to compare the first output voltage with a first reference voltage; 
 a first on-time control circuit arranged to output a signal in response to the first switching pulse signal after a lapse of a first on-time; and 
 a first flip-flop arranged to output the first switching pulse signal in response to the signal from the first voltage comparator and the signal from the first on-time control circuit. 
 
     
     
       3. The switching regulator control circuit according to  claim 2 ,
 wherein the first flip-flop is set according to the signal from the first voltage comparator, and is reset according to the signal from the first on-time control circuit. 
 
     
     
       4. The switching regulator control circuit according to  claim 1 ,
 the second switching signal generating circuit comprising: 
 a second voltage comparator arranged to compare the second output voltage with a second reference voltage; 
 a second on-time control circuit arranged to output a signal in response to the second switching pulse signal and the first switching pulse signal after a lapse of a second on-time; and 
 a second flip-flop arranged to output the second switching pulse signal in response to the signal from the second voltage comparator and the signal from the second on-time control circuit. 
 
     
     
       5. The switching regulator control circuit according to  claim 4 ,
 wherein the second flip-flop is set according to the signal from the second voltage comparator, and is reset according to the signal from the first on-time control circuit. 
 
     
     
       6. A switching regulator comprising the switching regulator control circuit according to  claim 1 , and a switching element turned on/off by the switching control circuit. 
     
     
       7. An electronic device comprising:
 a voltage source arranged to generate a predetermined DC voltage, and 
 the switching regulator according to  claim 6  arranged to boost or drop the predetermined DC voltage and arranged to output the resultant voltage to a load.